Rifaximin: A Review of Its Use in Reducing Recurrence of Overt Hepatic Encephalopathy Episodes

Management of minimal and overt hepatic encephalopathy with branched-chain amino acids: a review of the evidence

Hepatic encephalopathy (HE) is a challenging complication of liver disease that is associated with substantial morbidity and mortality. Branched-chain amino acid (BCAA) supplementation in the management of HE is a debated topic. This narrative review aims to provide an up-to-date review of the topic and includes studies featuring patients with hepatocellular carcinoma. A review of the literature was performed using the online databases MEDLINE and EMBASE for studies between 2002 and December 2022. Keywords 'branched-chain amino acids', 'liver cirrhosis' and 'hepatic encephalopathy' were used. Studies were assessed for inclusion and exclusion criteria. Of 1045 citations, 8 studies met the inclusion criteria. The main outcomes reported for HE was changed in minimal HE (MHE) (n = 4) and/or incidence of overt HE (OHE) (n = 7). Two of the 4 studies reporting on MHE had improvement in psychometric testing in the BCAA group, but there was no change in the incidence of OHE in any of the 7 papers in the BCAA group. There were few adverse effects of BCAA supplementation. This review found weak evidence for BCAA supplementation for MHE, and no evidence for BCAAs for OHE. However, given the relative paucity and methodological heterogeneity of the current research, there is scope for future studies to examine the effects of varying timing, dosage, and frequency of BCAAs on outcomes such as HE. Importantly, research is also needed to examine BCAAs in conjunction with standard therapies for HE such as rifaximin and/or lactulose.

Implications of anaemia and response to anaemia treatment on outcomes in patients with cirrhosis

Background & Aims

Anaemia is frequently observed in patients with cirrhosis and was identified as a predictor of adverse outcomes, such as increased mortality and occurrence of acute-on-chronic liver failure. To date, the possible effects of iron supplementation on these adverse outcomes are not well described. We therefore aimed to assess the role of iron supplementation in patients with cirrhosis and its capability to improve prognosis.

Methods

Laboratory diagnostics were performed in consecutive outpatients with cirrhosis admitted between July 2018 and December 2019 to the University Hospital Essen. Associations with transplant-free survival were assessed in regression models.

Results

A total of 317 outpatients with cirrhosis were included, of whom 61 received a liver transplant (n = 19) or died (n = 42). In multivariate Cox regression analysis, male sex (hazard ratio [HR] = 3.33, 95% CI [1.59, 6.99], p = 0.001), model for end-stage liver disease score (HR = 1.19, 95% CI [1.11, 1.27], p <0.001) and the increase of haemoglobin levels within 6 months (ΔHb6) (HR = 0.72, 95% CI [0.63, 0.83], p <0.001) were associated with transplant-free survival. Regarding the prediction of haemoglobin increase, intake of rifaximin (beta = 0.50, SD beta = 0.19, p = 0.007) and iron supplementation (beta = 0.79, SD beta = 0.26, p = 0.003) were significant predictors in multivariate analysis.

Conclusions

An increase of haemoglobin levels is associated with improvement of transplant-free survival in patients with cirrhosis. Because the prediction of haemoglobin increase significantly depends on rifaximin and iron supplementation, application of these two medications can have an important impact on the outcome of these patients.

Impact and implications

Anaemia is very common in patients with cirrhosis and is known to be a predictor of negative outcomes, but little is known about the effect of iron substitution in these individuals. In our cohort, increase of haemoglobin levels improved transplant-free survival of patients with cirrhosis. The increase of haemoglobin levels was mainly induced by iron supplementation and was even stronger in the case of concomitant use of iron and rifaximin.

Clinical trial registration

UME-ID-10042.

Diethyl phosphite-mediated switchable synthesis of bis(imidazoheterocycles) derived disulfanes and sulfanes using imidazoheterocycles and octasulfur

A unique diethyl phosphite-mediated switchable synthesis of bis(imidazoheterocycle)-derived disulfanes and sulfanes using imidazoheterocycles with sulfur is reported. Moreover, imidazo[1,2-a]pyridine-indole derived thioethers were also realized.

Quality of life as a therapeutic objective in the management of hepatic encephalopathy and the potential role of rifaximin-α

OBJECTIVE

Quality of life (QoL) is impaired in patients with hepatic encephalopathy and rifaximin-α can improve QoL within 6 months. This study assessed the importance of QoL as a therapeutic objective in hepatic encephalopathy management; whether QoL is routinely assessed in hepatic encephalopathy patients in clinical practice and the role of rifaximin-α in this context.

METHODS

A survey was conducted of healthcare professionals (HCPs) from Europe and Australia involved in hepatic encephalopathy management. HCPs rated the importance of a range of therapeutic objectives on a 1-7 Likert scale (1 = not at all important; 7 = extremely important). HCPs were also required to provide three patient record forms (PRFs) based on their last three hepatic encephalopathy patients.

RESULTS

There were 218 HCP respondents, who provided 654 PRFs (patients treated with rifaximin-α, n = 347; patients not treated with rifaximin-α, n = 307). The mean Likert score was highest for the therapeutic objective 'improving a patient's QoL' (6.4), which was rated significantly more highly than all other therapeutic objectives, including 'reducing the patient's likelihood of hospital readmission' (6.1; P < 0.001) and 'preventing death of the patient' (6.1; P < 0.001). Despite this, only 28.3% of PRFs documented specific QoL data assessment. Patients receiving rifaximin-α were treated later in their disease course than those not receiving rifaximin-α.

CONCLUSIONS

HCPs consider QoL improvement the main therapeutic objective in hepatic encephalopathy management, but most do not explicitly assess QoL. Earlier introduction of rifaximin-α may safeguard QoL improvement even when QoL monitoring is not possible.

Review of Rifaximin: A Summary of the Current Evidence and Benefits Beyond Licensed Use

Antibiotic resistance in patients with cirrhosis continues to draw significant attention. With a propensity to frequent hospitalisations, patients with cirrhosis are subject to frequent antibiotic prescription. This increases their risk of developing resistance to one or more antimicrobial agents, making management of their condition particularly challenging. Despite advancements being made in the management of liver disease, mortality rates continue to rise: almost 5-fold in those <65 years of age while remaining the leading cause of death in those 35–49 years of age. Alternative therapeutic options to prevent disease progression and cirrhosis-associated complications are urgently required; rifaximin is one such example. The medication use in patients with cirrhosis demonstrates additional benefits beyond current licensed use in the UK, that being for the prevention of hepatic encephalopathy and traveller’s diarrhoea; rifaximin has especially been explored beyond current licensed use in the context of enteric-driven pathologies. Through the therapy’s key central action as a broad-spectrum antimicrobial, rifaximin has the ability to modulate the gut–liver axis via removal of gut microbial products associated with the progression of cirrhosis and its sequalae. The benefits of rifaximin use continues to gather momentum, given its non-absorbable nature and well-tolerated side-effect profile, and these require consideration. With broad-spectrum antimicrobial properties, its use may assist in overcoming the conundrum posed of antibiotic resistance amongst patients with cirrhosis. This literature review discusses the chemical and antimicrobial properties of rifaximin, its licenced indication for use, and its reported benefits beyond this, as well as concerns regarding rifaximin resistance.

The Use of Rifaximin in Patients With Cirrhosis

Rifaximin is an oral nonsystemic antibiotic with minimal gastrointestinal absorption and broad-spectrum antibacterial activity covering both gram-positive and gram-negative organisms. Rifaximin is currently used worldwide in patients with cirrhosis for preventing recurrent HE because its efficacy and safety have been proven by large randomized clinical trials. In the last decade, experimental and clinical evidence suggest that rifaximin could have other beneficial effects on the course of cirrhosis by modulating the gut microbiome and affecting the gut-liver axis, which in turn can interfere with major events of the pathophysiological cascade underlying decompensated cirrhosis, such as systemic inflammatory syndrome, portal hypertension, and bacterial infections. However, the use of rifaximin for prevention or treatment of other complications, including spontaneous bacterial peritonitis or other bacterial infections, is not accepted because evidence by clinical trials is still very weak. The present review deals in the first part with the potential impact of rifaximin on pathogenic mechanisms in liver diseases, whereas in the second part, its clinical effects are critically discussed. It clearly emerges that, because of its potential activity on multiple pathogenic events, the efficacy of rifaximin in the prevention or management of complications other than HE deserves to be investigated extensively. The results of double-blinded, adequately powered randomized clinical trials assessing the effect of rifaximin, alone or in combination with other drugs, on hard clinical endpoints, such as decompensation of cirrhosis, acute-on-chronic liver failure, and mortality, are therefore eagerly awaited.

Synthesis of naphtho[1′,2′:4,5]imidazo[1,2-a]pyridines via Rh(iii)-catalyzed C–H functionalization of 2-arylimidazo[1,2-a]pyridines with cyclic 2-diazo-1,3-diketones featuring with a ring opening and reannulation

An unprecedented synthesis of functionalized naphtho[1′,2′:4,5]imidazo[1,2-a]pyridines via rhodium-catalyzed cascade reactions of 2-arylimidazo[1,2-a]pyridine-3-carbaldehydes with cyclic α-diazo-1,3-diketones is presented.

Long-term management of hepatic encephalopathy with lactulose and/or rifaximin: a review of the evidence

A consolidated overview of evidence for the effectiveness and safety/tolerability of hepatic encephalopathy (HE) treatment over the long term is currently lacking. We identified and assessed published evidence for the long-term (≥6 months) pharmacological management of HE with lactulose and/or rifaximin. A literature search was conducted in PubMed (cutoff date 05 March 2018) using the search terms 'hepatic encephalopathy+rifaximin' and 'hepatic encephalopathy+lactulose'. All articles containing primary clinical data were manually assessed to identify studies in which long-term (≥6 months) effectiveness and/or safety/tolerability end points were reported for lactulose and/or rifaximin. Long-term effectiveness outcomes were reported in eight articles for treatment with lactulose alone and 19 articles for treatment with rifaximin, alone or in combination with lactulose. Long-term safety/tolerability outcomes were reported in six articles for treatment with lactulose alone and nine articles for treatment with rifaximin, alone or in combination with lactulose. These studies showed that lactulose is effective for the prevention of overt HE recurrence over the long term and that the addition of rifaximin to lactulose significantly reduces the risk of overt HE recurrence and HE-related hospitalization, compared with lactulose therapy alone, without compromising tolerability. Current evidence therefore supports recommendations for the use of lactulose therapy for the prevention of overt HE recurrence over the long term, and for the additional benefit of adding rifaximin to lactulose therapy. Addition of rifaximin to standard lactulose therapy may result in substantial reductions in healthcare resource utilization over the long term, by reducing overt HE recurrence and associated rehospitalization.

Design of the Prospective Real-world Outcomes Study of hepatic encephalopathy Patients' Experience on Rifaximin-α (PROSPER): an observational study among 550 patients

Background

Hepatic encephalopathy (HE) is one of the most important severe complications of liver cirrhosis. Thought to be caused by elevated blood levels of gut-derived neurotoxins (particularly ammonia) entering the brain, HE manifests as a wide range of neurological or psychiatric abnormalities, which increase the risk of mortality, result in substantial morbidity and negatively affect the quality of life (QoL) of both patients and their caregivers. HE is also associated with a substantial economic burden. Rifaximin-α 550 mg is a locally acting oral antibiotic that reduces the effects of ammonia-producing intestinal flora, and which is used to help reduce the recurrence of overt HE. The efficacy of rifaximin-α 550 mg was established in a randomised controlled trial and long-term extension study. However, ‘real-world’ evidence is also required to assess how this efficacy may translate into effectiveness in clinical practice, including the potential impact of treatment on healthcare resource utilisation.

Methods

The Prospective Real-world Outcomes Study of HE Patients’ Experience on Rifaximin-α 550 mg (PROSPER) is a multinational, multicentre, observational study that will be conducted under real-world clinical practice conditions. Comprising a retrospective phase (up to 12 months) and a prospective phase (up to 24 months), and employing a robust statistical methodology, PROSPER has been specifically designed to minimise the bias associated with observational studies. The primary endpoint will be the effect of rifaximin-α 550 mg treatment on HE- and liver-related hospitalisation rate and duration of hospitalisation. Secondary endpoints will include comprehensive assessments of the impact of treatment on the QoL and workplace productivity of patients and caregivers, a global assessment of treatment effectiveness and safety/tolerability. Approximately 550 patients will be enrolled.

Conclusions

PROSPER will provide valuable real-world information on the effectiveness of rifaximin-α 550 mg in reducing the recurrence of HE, and its impact on the QoL and work productivity of patients and their caregivers. By providing data on both the direct costs (e.g., hospitalisation rate, duration of hospitalisation) and indirect costs (such as work productivity) of HE, PROSPER should help confirm whether rifaximin-α 550 mg treatment represents a good use of economic resources.

Trial registration

ClinicalTrials.gov identifier NCT02488993.

The Effects of Probiotics and Symbiotics on Risk Factors for Hepatic Encephalopathy: A Systematic Review

Alterations in the levels of intestinal microbiota, endotoxemia, and inflammation are novel areas of interest in the pathogenesis of hepatic encephalopathy (HE). Probiotics and symbiotics are a promising treatment option for HE due to possible beneficial effects in modulating gut microflora and might be better tolerated and more cost-effective than the traditional treatment with lactulose, rifaximin or L-ornithine-L-aspartate. A systematic search of the electronic databases PubMed, ISI Web of Science, EMBASE, and Cochrane Library was conducted for randomized controlled clinical trials in adult patients with cirrhosis, evaluating the effect of probiotics and symbiotics in changes on intestinal microflora, reduction of endotoxemia, inflammation, and ammonia, reversal of minimal hepatic encephalopathy (MHE), prevention of overt hepatic encephalopathy (OHE), and improvement of quality of life. Nineteen trials met the inclusion criteria. Probiotics and symbiotics increased beneficial microflora and decreased pathogenic bacteria and endotoxemia compared with placebo/no treatment, but no effect was observed on inflammation. Probiotics significantly reversed MHE [risk ratio, 1.53; 95% confidence interval (CI): 1.14, 2.05; P=0.005] and reduced OHE development (risk ratio, 0.62; 95% CI: 0.48, 0.80; P=0.0002) compared with placebo/no treatment. Symbiotics significantly decreased ammonia levels compared with placebo (15.24; 95% CI: -26.01, -4.47; P=0.006). Probiotics did not show any additional benefit on reversal of MHE and prevention of OHE development when compared with lactulose, rifaximin, and L-ornithine-L-aspartate. Only 5 trials considered tolerance with minimal side effects reported. Although further research is warranted, probiotics and symbiotics should be considered as an alternative therapy for the treatment and management of HE given the results reported in this systematic review.

Second prophylaxis of variceal bleeding in cirrhotic patients with a high HVPG

OBJECTIVE

The hepatic venous pressure gradient (HVPG) could be used to stratify patients in different risk groups. No studies have reported the role of transjugular intrahepatic portosystemic shunt (TIPS) placement in a subgroup of patients with a high HVPG (≥20 mmHg) for secondary prophylaxis of variceal bleeding. This study was designed to evaluate the benefit of TIPS in cirrhotic patients with a high HVPG (≥20 mmHg) for rebleeding and survival.

MATERIAL AND METHODS

We included 46 cirrhotic patients with a history of variceal bleeding and a high HVPG (≥20 mmHg) admitted to our hospital between January 2013 and June 2014 (TIPS group). Patients were matched by Child-Pugh scores to patients in our historical cohort hospitalized for prophylaxis of variceal rebleeding between April 2011 and December 2012 (propranolol + EVL group). The end points included time to significant rebleeding from portal hypertensive sources, 1-year survival, and time to the occurrence of hepatic encephalopathy (HE).

RESULTS

The 1-year actuarial probability of remaining free of variceal rebleeding was significantly higher in the TIPS group than in the propranolol + EVL group (85% vs. 54%, p = 0.01). The 1-year survival rates were not different between the two groups (85% vs. 89%, p = 0.591). The 1-year actuarial probability of remaining free of HE was significantly lower in the TIPS group than in the propranolol + EVL group (67% vs. 91%, p = 0.003).

CONCLUSIONS

TIPS was more effective than propranolol + EVL in preventing variceal rebleeding in cirrhotic patients with a high HVPG (≥20 mmHg). During the limited follow-up, survival was similar in the two groups.

Rifamycins, Alone and in Combination

Rifamycins inhibit RNA polymerase of most bacterial genera. Rifampicin remains part of combination therapy for treating tuberculosis (TB), and for treating Gram-positive prosthetic joint and valve infections, in which biofilms are prominent. Rifabutin has use for AIDS patients in treating mycobacterial infections TB and Mycobacterium avium complex (MAC), having fewer drug-drug interactions that interfere with AIDS medications. Rifabutin is occasionally used in combination to eradicate Helicobacter pylori (peptic ulcer disease). Rifapentine has yet to fulfill its potential in reducing time of treatment for TB. Rifaximin is a monotherapeutic agent to treat gastrointestinal (GI) disorders, such as hepatic encephalopathy, irritable bowel syndrome, and travelers' diarrhea. Rifaximin is confined to the GI tract because it is not systemically absorbed on oral dosing, achieving high local concentrations, and showing anti-inflammatory properties in addition to its antibacterial activity. Resistance issues are unavoidable with all the rifamycins when the bioburden is high, because of mutations that modify RNA polymerase.

[Role of rifaximin in the treatment of hepatic encephalopathy]

Hepatic encephalopathy (HE) is a frequent and serious complication of liver cirrhosis. In addition to correction of the precipitating factors, the most commonly used treatments are non-absorbable disaccharides and rifaximin. Many of the recommendations are based on current clinical practice and there are few randomized controlled trials. Currently, rifaximin should be initiated during an episode of EH if, after 24-48 hours of non-absorbable disaccharide therapy, there is no clinical improvement. In recurrent EH, it is advisable to add rifaximin in patients under non-absorbable disaccharide therapy who develop a new episode. Currently, standard treatment with rifaximin for minimal EH is not recommended. Rifaximin is effective in the acute treatment of overt encephalopathy and in preventing recurrence.

Palliative care for patients with end-stage liver disease

Liver disease results in over four million physician visits and over 750,000 hospitalizations per year in the USA. Those with chronic liver disease frequently progress to cirrhosis, end-stage liver disease (ESLD), and death. Patients with ESLD experience numerous complications, including muscle cramps, confusion (hepatic encephalopathy), protein calorie malnutrition, muscle wasting, fluid overload (ascites, edema), bleeding (esophagogastric variceal hemorrhage), infection (spontaneous bacterial peritonitis), fatigue, anxiety, and depression. Despite significant improvements in palliation of these complications, patients still suffer reduced quality of life and must confront the fact that their disease will often inexorably progress to death. Liver transplantation is a valid option in this setting, increasing the duration of survival and palliating many of the symptoms. However, many patients die waiting for an organ or are not candidates for transplantation due to comorbid illness. Others receive a transplant but succumb to complications of the transplant itself. Patients and families must struggle with simultaneously hoping for a cure while facing a life-threatening illness. Ideally, the combination of palliative care with life-sustaining therapy can maximize the patients' quality and quantity of life. If it becomes clear that life-sustaining therapy is no longer an option, these patients are then already in a system to help them with end-of-life care.

Early to Phase II drugs currently under investigation for the treatment of liver fibrosis

INTRODUCTION

Chronic liver diseases represent a high unmet medical need and are characterized by persistent inflammation, parenchymal damage and fibrotic remodeling, leading eventually to cirrhosis and hepatic failure. Besides the persisting high prevalence of chronic viral hepatitis B and C, the dramatic increase in nonalcoholic steatohepatitis is now considered to be a major pathophysiologic driver for fibrosis development and subsequently cirrhosis. Increasing evidence suggests that also liver cirrhosis can regress when treated adequately.

AREAS COVERED

Herein, the authors review the underlying pathophysiologic mechanisms leading to fibrotic remodeling in the liver. They also highlight the options for novel treatment strategies by using molecular targeted agents.

EXPERT OPINION

New in vitro and preclinical animal models, and the careful selection of patients with high disease dynamics for clinical studies, provide a sound basis for the clinical development of antifibrotic agents in humans. Surrogate parameters of liver function, inflammation, tissue remodeling and damage, as well as noninvasive imaging techniques, can be applied in clinical trials to provide fast readouts and novel and reliable endpoints for trial design, and provide an attractive regulatory environment for this emerging disease area.